1. Field of the Invention
The present invention relates to an ink-receiving composite polymer material, particularly to a composite polymer which is useful as recording media for ink-jet recording.
2. Related Background Art
Various polymer materials comprising one or a plurality of components are conventionally known. Composite polymer materials comprising a plurality of components include materials in which these components are uniformly distributed over the whole of the resultant polymer formation and materials which exhibit a component gradient within the resultant polymer formation.
Examples of materials having component gradients include the following:
(1) materials comprising one or more polymer films laminated on a polymer substrate;
(2) materials obtained by applying one or more polymer solutions to a polymer substrate so as to form layers;
(3) materials in which monomers or oligomers are mixed and, during the polymerization thereof, the composition of an unreacted system is gradually changed, resulting in a component gradient through the whole of the resultant polymer formation; and
(4) materials in which two or more kinds of monomers and/or polymers are mixed and a polymer formation having a sea-island structure is obtained by controlling the solubilities in a solvent or the compatibilities of the polymers to one another.
These sorts of composite polymer materials have been employed for various applications, particularly for materials relating to printing, adhesives, and structural materials, for a long time. These polymer materials have recently been employed for lenses with varying refractive indexes and optical elements such as optical wave guides.
Recently to produce recording media for various types of printer, one or a plurality of recording layers (ink-receiving layers) has been formed on the surface of paper or a plastic film as a substrate, using various polymer solutions, for the purpose of improving the suitability of such media for recording.
In polymer formations obtained by the above-described methods (1) or (2), the component gradient exhibits a plurality of layers and so, there interfaces between the layers. The presence of these interfaces prevents continuous progresses of energy during the propagation of optical or vibrational energy through the polymer forming, so that an energy loss is likely to occur. In addition, a similar problem is produced by the discontinuity of the interfaces during the passage of light as well as substances such as molecules or ions. The presence of the interfaces also produces a physical problem in that ply separation can easily occur.
In the case of the polymer formations by the above-mentioned method (3), since the materials which penetrate thereinto and are diffused therethrough are monomers and oligomers, a process of reaction and polymerization is necessary to fix these materials, and thus there are problems with respect to the difficulty in controlling the component gradient, the reproducibility of materials, and the difficulty in the production of composite polymer formations having uniform quality.
In the case of the polymer formations by the above-mentioned method (4), since the component gradient is formed by differences in solubility and compatibility, the component gradient is random, and it is impossible to obtain uniform component gradients.
When the polymer formations by the above-mentioned method (2) are used as, for example, recording media for the ink-jet recording method using an aqueous ink, there are problems relating to the absorption of ink in that it is difficult to control ink absorbency, the ink diffuses into the interfaces between the layers, and is prevented from being absorbed, and problems with respect to adhesion and ply separation due to poor adhesion properties.